Improvement in carriage-jacks



Z. McDONALD.

Carriage-lack.

Patented Oct. 26,1875.

Win 5555:

KM ,v 1 @WM N. PETERS, PHOTO-LITKOGRAPHER, WASHINGTON. D c. 7

UNITED STATES PATENT OFFICE.

ZIMRI MCDONALD, OF WASHINGTON, DISTRICT OF GOLUMBIA.

IMPROVEMENT IN CARRIAGE-JACKS- Specification forming part of Letters Patent No. 169,279, dated October 26, 1875; application filed October 16, 1875.

To all whom it may concern:

Be it known that I, ZIMRI MCDONALD, of Washington, in the county of Washington and District of Columbia, have invented certain Improvements in Carriage-Jacks, of which the following is a specification:

My invention relates to carriage-jacks; and the invention consists in a weighted catch arranged to operate in combination with the operating-lever, as hereinafter more fully set forth.

- Figure 1 is aside elevation showing the lever held down by the catch 5 and Fig. 2 is a side elevation, partly in section, showing the lever released from the catch.

1n constructing my jack I provide a base, B, to which is secured a standard, A, having a mortisedhead-piece, G, in or through which the sliding rack D moves up and down. To the upper part of the standard A is pivoted a lever, L, which has a segmental head, a, provided with a series of teeth, as shown in Fig. 2, these teeth being arranged to engagewith the teeth of rack D as the lever is depressed, as represented in Fig. 2. By raising or lowering the lever L the rack D is thus raised or lowered at will, and when it is desired to change the position of the rack the segmental teeth can be disconnected therefrom by raising the lever, as shown in Fig. 2, when the bar D can be slid up or down to any desired position and the teeth engaged therewith again by dropping the lever.

Heretofore, in this class of jacks, there has been a spring-catch used to lock the lever fast when in use; but this is objectionable for several reasons. It had to be made of steel, forged and tempered, and was therefore expensive. It was, moreover, liable to break, especially in frosty weather, and is somewhat difficult to operate.

To obviate these objections Iconstruct my jack with a pivoted catch, 0, as represented in Figs. 1 and 2. This catch is constructed with a lip or hook-like projection, e, at one end, as shown in Fig. 2, while its opposite end is made much heavier, so as to overbalauce the hooked end and cause it to be raised, as shown in Fig; 2, when detached from the lever L. catch 0 is pivoted or journaled in a plate or bearings, c, secured firmly upon the base A in such a position that when the leverL is depressed its flattened end will engage with the hooked end 6, as represented in Fig. 1. The hooked end of the catch is beveled, so that, as the lever strikes it, it is depressed, the lever sliding over the hook, when the weighted or opposite end at once causes the hook to engage with the end of thelever and hold it fast. To release the lever, the foot is pressed on the projecting end of the catch and the lever, when, by pressing down slightly on the catch, it is detached from the lever, which is permitted to rise by gradually raising thefoot. This catch 0, with its plate or bearings 0, can be cast at a trifling expense, is not liable to break, and can be operated in the simplest possible manner If desired, the base B, with the standard A, may all be cast together, in which case the plate or bearings 0 may be cast with the base in the form of ,ZIMRI MCDONALD.

' Witnesses:

. W. G. DODGE,

DoNN TWITcHELL.

This 

